The present invention relates to a pin type disc brake for use in a vehicle, more particularly to the pin type disc brake having an improved slide support mechanism thereof.
Generally, a pin type disc brake is known to be installed so as to stride over a periphery of a rotatable disc. The pin type disc brake is provided with a caliper which urges a pair of friction pads into frictional engagement with the disc and a support member supporting the caliper to be movable on the axis of the disc. The support member is fixed to a stationary part of the vehicle at one side of the disc and extends to the vicinity of the periphery of the disc. The slide support mechanism is provided with a guide pin fixed to one of the caliper and the support member, which pin is slidably fitted to a through hole provided in the other of the caliper and the support member.
In case of a disc brake of a relatively large size, a guide pin is inserted into a through hole provided in a support member directly or through a sleeve so as to slidably be fitted to the through hole, and both ends of the guide pin are engaged with a pair of extension arms formed on the caliper. Normally, there may be a pair of such a slide support mechanism installed at both the sides of the caliper which is separately disposed on a circumferential direction of the disc.
In the slide support mechanism thus constructed, it is required to simplify the insertion and removal of the guide pin in consideration of protecting a slide supporting surface and exchanging the friction pads, to simplify the workability in assembling the mechanism, to reduce the number of parts, to reduce the weight of parts such as a guide pin and the like while maintaining a required mechanical strength and durability, and so forth. In the disc brake of relatively large size as mentioned above and disclosed in U.S. Pat. No. 4,084,666, a guide pin is inserted into a through hole formed in a support member being slidable therewith. Both the ends of the guide pin are fitted in boss holes of a pair of extension arms formed on the caliper, so that the pair of extension arms are fastened tight by a large diameter head formed at one side of the guide pin and a nut screwed to a threaded part formed at the other side of the guide pin. However, such a structure would be disadvantageous in that an extension force as a reaction of the fastening would be applied to the guide pin.
Further, in the conventional disc brake, a load is applied to the caliper when the brake is actually performed and, therefore, an extra large extension force would be applied to the guide pin. For this reason, the guide pin has been required to have a relatively large diameter since when a pair of friction pads are urged into frictional engagement with the rotating disc, as a reaction of this, a large force is applied to the caliper, which force acts to expand the pair of arms of the caliper.